Development of a Tiny
Orientation Estimation Device to Operate under Motion and Magnetic Disturbance

T. Harada, T. Mori, and T. Sato Graduate School of Information Science and Technology,
The University of Tokyo

A tiny absolute orientation estimating device equipped with a network
function has been developed using accelerometers and magnetometers
to estimate gravity and the geomagnetic field, respectively.
Because accelerometers measure motion other than gravity,
a method has been proposed to eliminate the effect of motion. An
estimation method is proposed that excludes the effect of magnetic
disturbances. An advantage of this estimation method is that models
can be switched according to the environment. Sigma Points Kalman
Filters (SPKFs) were evaluated to determine the proper filter for the
proposed algorithm. A Square-Root Central Difference Kalman Filter
(SR-CDKF) was the best method considering stability, accuracy,
and calculation cost. Using simulations and the realized device, the
proposed algorithm stably estimated the orientation in the presence
of motion and magnetic disturbances.